Not Applicable
Not Applicable
1. Field of the Invention
The present invention relates to a golf club head. More specifically, the present invention relates to a compliant face section of a golf club head to reduce energy losses when impacting a golf ball.
2. Description of the Related Art
Technical innovation in the material, construction and performance of golf clubs has resulted in a variety of new products. The advent of metals as a structural material has largely replaced natural wood for wood-type golf club heads, and is but one example of this technical innovation resulting in a major change in the golf industry. In conjunction with such major changes are smaller scale refinements to likewise achieve dramatic results in golf club performance. For example, the metals comprising the structural elements of a golf club head have distinct requirements according to location in the golf club head. A sole or bottom section of the golf club head should be capable of withstanding high frictional forces for contacting the ground. A crown or top section should be lightweight to maintain a low center of gravity. A front or face of the golf club head should exhibit high strength and durability to withstand repeated impact with a golf ball. While various metals and composites are known for use in the face, several problems arise from the use of homogeneous and non-homogeneous face structure.
A non-homogeneous face structure typically involves an insert centrally located which requires an exacting fit between two or more distinct elements, but has the advantage of utilizing beneficial material properties in a combination which is not available in each material individually. A homogeneous face structure is simpler to manufacture but is limited to the inherent material properties of one material. The present invention achieves the performance advantages of a non-homogeneous face structure with a simpler homogeneous construction.
The present invention comprises an improved structure to reduce energy loss during impact of a golf club head with a golf ball. In a preferred embodiment the golf club head is a wood-type golf club head with a plurality of walls to define a hollow interior. During impact both the golf club head and the golf ball will compress, followed by the golf ball leaving the face of the golf club head where both the golf club head and the golf ball will experience a decaying vibration mode before returning to their respective original shapes. By allowing the golf club head to flex and xe2x80x9ccradlexe2x80x9d the golf ball during impact the internal stress in the golf ball is reduced, leading to a longer duration and more energy conserving impact. Extending the contact time of the golf ball with the face of the golf club reduces energy lost in the golf ball. By producing an channel or recess in one or more walls of the golf club head the contact time of the golf ball will increase as the linear distance the face travels during impact is increased. This channel defines a thin or minimum wall thickness in one or more sections of the golf club head. The face of the golf club head can be constructed from rigid material and still obtain the benefits of the present invention.
Shape and location of the recess determines important performance variables including durability, coefficient of restitution (COR) and angular deflection. Walls of the recess should be smoothly contoured to accommodate bending stresses from golf ball impact while allowing the face to move rearwardly in the golf club head without altering the face orientation.
Coefficient of restitution (COR) is well known to those of ordinary skill in the art, and is defined as the ratio of the of the golf ball velocity over the golf club head velocity, where velocity is measured before and just after impact of the golf ball with the golf club head.
Expressed mathematically, the equation is outlined below:   COR  =                    V                  2          ⁢                      xe2x80x83                    ⁢          ball                    -              V                  1          ⁢                      xe2x80x83                    ⁢          ball                                    V                  1          ⁢                      xe2x80x83                    ⁢          club          ⁢                      xe2x80x83                    ⁢          head                    -              V                  2          ⁢                      xe2x80x83                    ⁢          club          ⁢                      xe2x80x83                    ⁢          head                    
where V2 ball is the velocity of the golf ball measured immediately after impact with the golf club head; V1 ball is the velocity of the golf ball measured immediately before impact with the golf club head; V1 club head is the velocity of the golf club head measured immediately before impact with the golf ball; V2 club head is the velocity of the golf club head measured immediately after impact with the golf club head.
One object of the present invention is to improve impact efficiency between a golf club head and the golf ball.
Another object is to allow a rigid material to perform as a compliant golf club face. Any number of rigid materials can be utilized in the manufacture of the golf club of the present invention to produce a compliant, or softer flexing performance during impact with the golf ball.
A further object of the present invention is a wood-type golf club head having an internal channel for flexing of the golf club face.
Another object of the present invention is a wood-type golf club head having an external channel for flexing of the golf club face.
Another object of the present invention is a golf club head comprising a face cup containing a channel.
Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.